Variable speed governor



Feb. 23, 1954 I F. A. MASHERIS m1. 2,670,416

VARIABLE SPEED GOVERNOR Filed April 22, 1948 2 Sheets-Sheet l 'F 23,1954 F. A. MASHERIS E1- AL 2,670,416

VARIABLE SPEED GOVERNOR Filed April 22, 1948 2 Sheets-Sheet 2 Men/flowPatented Feb. 23, 1954 UNITED STATES PATENT OFFICE VARIABLESPEED'GOVERNOR Fred A. Masher-is and Kalman Tanko; Chicago,

111., assignors to Dormeyer Corporation, Chicage, Ill., a corporation ofIllinois- Application'April 22, 1948; Serial'No. 27,044

23 Claims. 1

The invention relates to speed control governorszfor electric motors,and morepartlcularly to'speed governors which are subjected to andinfluenced centrifugal force.

Although the invention is shown and described in connection. withufoodmixers, it may be used with motors in other devices also.

In order tounderstand the invention, and particularly its applicationtofood mi..ers, it shoul lie-noted that food mixers for a long time,employed two interdlgitating heaters f the'iood mixing and beatingoperations generally encountered in'home kitchens. Series wound factional horsepower. vmotors are favored of the advantages derived from.the torque s acteristics of thesemotorstheir adapts speedcontiol. andtheir universal availaoili AFC. and-D. C. current operation.

Armature speeds on such motors run as high as 20,360 R. .P; M. outgenerallyhave a top speed in the neighborhood of 14,099 to 16,000 R. liZ. when they are driving gear trains such as those normally used in foodmixers.

It has 'beenfoundthat the topspeedoi the interdigitating heaters shouldbe in the neighborhood of 1009 R. P. M. and this. requires a gearreduction ratio between the armature shaft and the beater shaf s ofapproximately 15 to 1.

lrrorder for the food mixers to have a general alt-round use in thekitchen, lower heater speeds are required and the range of governedspeeds heretofore provided extends from 1908 R. P. M.

down to 3 36 R. P. M. depending upon. the task to be performed. This isaccomplished by centrifugalgovernors' interrupting all or part of theelectric current impressed upon the motor so that the Speed isinfinitely variable within. the range.

These centrifugal governors constitutes switch have been'generally oftwo types; One type comrises nonrotating switchcontacts, one ofwhich isdisplaced by a train of elements actuated by a centrifugal responsivedevice driven by, the armature shaft of the motor. With this-type,however, friction present in. the train of movingelements detractsmaterially front satisfactory performance. The other type comprisesrotating switch contacts, one of which is displacedby the governorsheretofore" employed:

actionioi' centrifugalforce applied directly thereto. This latter typeis probably the better of the two but still not satisfactory at thelower speeds, particularly where A. C. currents are em ployed. In fact,the 380 R. P. M. lower limit heretofore provided is the minimum speedpossible with. present centrifugal governors without encounteringobjectionable pulsation; Spurting or loping of the motor, arcing at theswitch contacts and a hammering effect of the mixer.

At this minimum speed of 300 R. P.'M. the so not correctly foldingredients into food mixtures. Food ingredients; especiallydiy'inere-clients such as flour, are thrown out of the bowl when theyare supposed to be folded into the mixture, and furthermore this speedis not low enough for many food mixing operations. such as the'stirringand beating of candy, the mashin oi potatoes, the folding of egg Whitesinto batter, etc.

Consequently, the industry has long felt the need of a governor of thecurrent interruptanc'e type which will function simply andsatisfactorily throughout a speed range which extends as low as 1% R. P.M. for the beatershafts of interdigitating heaters.

By Wayof understanding this problem better,

itshould be noted that conventional centrifugal control switches areconnected in series with the motor circuitand in parallel with bothraballast resistance and a spark suppressing condenser Reference is herebymade to the Behar Patent No. 2,262,912 for a more complete explanationthereof. Furthermoraas pointed out in the Lee Patent No. 2,193,589, theswitches heretofore used vibrate to make and break the'circuit at a rateof from 50 to 380 times a second. The rate is lower when the motor isnot operating under a load and alsovarie-s with the ohms present in thehall-astresi-stor. If the resistance is high, in the neighborhood of 250ohms, the switch makes and breaks with greater frequency than if theresistor is 150 ohms. On the other hand; the lower the resistance is,the greater the heat generated in it because the motor runs-more uponthe resistance.

It has been found in connection with the present invention thatapproximately 200 ohms isthe preferred minimum resistance to beconnected in parallel with the switch contacts in order to attain aminimum beater speed of 100 R. P; M. with a motor whose stall amperageis approximately 5 amperes 117 volts D.'C. It is also to be- With a 200ohm resistance, the nonloaded make and break frequency of thecentrifugal switch at 380 R. P. M. beater speed is conventionally lessthan 100 times a second, depending somewhat upon the length of the leafspring which supports the centrifugally displaced contact. This causesthe motor to spurt and lope due to the fact that the makes persist toolong and the breaks are not spaced evenly. Furthermore, the makes andbreaks tend to group themselves due to the harmonic vibration of theresilient element subjected to the centrifugal force. Not only is thistendency to group a factor in causing pulsations or spurts of the motorat the lower speeds but when the governor is moved to provide higherspeeds, 1

or where the governor make and break vibration i a speed governor whichoperates smoothly and evenly throughout the range of from 1500 R. P. M.to 15,000 R. P. M. armatur speeds.

Another object of the invention is to provide a predetermined tensionbetween centrifugally actuated switch contacts and maintain said tensionconstant throughout a wide range of speed controlling adjustments.

Another object of the invention is to provid a food mixer which operatessmoothly and efiicient- 1y at speeds low enough that dry ingredients arenot thrown out of the bowl by the heaters and at which whipped eggwhites can be folded into a mixture without deleterious effects.

is higher than 100 times a second, this tendency to group approaches afrequency of approximately 6% cycles at middle speeds and causes anaudible frequency beat effect in the motor when the motor is connectedto 60 cycle A. C. current. This is particularly true where the tensionon the resilient element of the governor is centrifugally or manuallyvaried throughout that particular part of the speed range.

The shorter the spring is, of course, the greater will be the frequency,provided the shortness of the spring is not counteracted by asubstantial weight increment on the spring creating a lower frequency.But the spring cannot be short enough in conventional constructions todo much good The wide range of speeds over which the governor performsand the necessary bodily displacement of associated elements employed,requires that the spring supporting the centrifugal contact be ofsuiiicient length that it will not fatigue or be extended beyond itselas ic limit by the widely varying tensions and fieXure loads imposedupon it throughout its range of adjustment. Thus, being confronted withthese difficulties, shorter springs to increase the frequency of currentinterruptanoe have not been possible heretofore and the 300 R. P. M.beater speed has been considered to be minimum for governors on foodmixers compatible with acceptably smooth running operation of the motor.

In the present invention beater speeds can be provided as low as 100 R.P. M. without sacrificing any smoothness of operation or motor power,the shunting resistance remaining for example at 200 ohms. However,since 100 R. P. M. beater speed is well below that which is practicalfor operating interdigitating heaters, and is mentioned here forcomparison and other possible applications, the lowest limit that may bedesired can now be provided in food mixers quite easily. Preferably, itis from 150 to 200 R. P. M. on the beater shafts. Translated intoarmature speeds, the lowest limit thus is less than 3000 R. P. M., whichspeeds are over a third less than that heretofore conventionallyattainabl with acceptable results in food mixers.

A further object of the invention resides in imposing upon a resilientmember capable of vibrating with a harmonic cycle, a secondary elementwhich is carried thereby loosely enough that it destroys the harmoniccycling by being a foreign element opposing same, yet is notsufficiently heavy to set up a dominant harmonic cycling of its own.

Another object of the present invention is to eliminate the tendency ofa centrifugally infiuenced governor to group its makes and breaks withrecurring frequency.

Another object of the invention is to provide Another object of thinvention is to provide a centrifugally influenced current interrupterswitch which provides over 300 makes and breaks a second even at lowspeeds, without cycling effect.

Another object of the invention is to eliminate all possiblecontamination, fouling or momentary arcing during the make and break ofa centrifugally influenced switch contact by disposing the contacts in asealed inert atmosphere, preferably under arc suppressing pressures.

A further object of the invention resides in providing a centrifugallyresponsive switch of a predetermined speed setting for interchangeableuse in food mixers without need for correction adjustments in the trainof elements by which the governor is controlled.

Another object of the invention is to provide a centrifugal speedgovernor capable of controlling the speed of a motor throughout a widerange of speeds without disturbing the dynamic balance of th motorthroughout the range.

The invention is further characterized by rotating the centrifugalgovernor in a direction whereby inertia of the centrifugally influencedswitch contact is employed to assist in closing the contacts when. themotor begins to slow up after an opening of the contacts.

Other objects of the invention, including simplicity of construction andoperation will appear from the drawings, the description relatingthereto, and the appended claims.

Referring now to the drawings:

Fig. 1 is a side elevationa1 view of a food mixer in which is embodiedthe present invention;

Fig. 2 is an enlarged cutaway view of a portion of the device shown inFig. l exposing to view partly in section a speed governor constructionembodying the invention;

Fig. 3 is a view of the construction shown in Fig. 2 partly in sectionas taken upon a. horizontal medial plane;

Fig. 4 is an end view of the governor shown in Figs. 2 and 3 as disposedin its normal resting position;

Fig. 5 is a view similar to Fig. 4 illustrating the position of thecontacts and supporting elements when the governor is in operation at acomparatively high speed;

Fig. 6 is a view similar to Fig. 4 showing a modification of theinvention when set to run at a low speed;

Fig. 7 is a view similar to Fig. 6 illustrating the position of theembodiment shown in Fig. 6 when set to run at high speeds;

Fig. 8 is an end. view of another modification of the invention whenpositioned to contro1 the operation of the motor at low speeds;

Fig. 9 is a section taken through the switch element shown in Fig. 8 inan early stage of its Construction;

5 3 mg. 1015 a view similar to Fig.3 showing" the mention ata subsequentstage of construction;

"Fig; 11 illustrates the; setting of the device shown in Fig. 1preliminary to its installation 'ina food mixer; and

Fig. 1'2 a "diagrammatic showing'of a preferred form of a motor circuitof which the invention fo'r'msa part.

The invention as embodied for purposes of desorption involves a leafspring su porting a switch contact eccentrically to an axis of rotationto subject it to centrifugal forces that operate to separate it from acooperating contact above a certain speed and to close it against theother contact below said predetermined speed, which speed is selectivelydeterminable at will. The spring preferably under initial tension and isalso subjected to further tension due to centrifugal rqrc'e'actmg uponit. An element is mounted loosely upon the spring intermediate its endsand in the' preferred form the spring is apertured intermediate its endsto receive the element 'therethrough in loose relationship, whichelement is of sufiicient weight to breakup harmonic action of the springbut of insufficient Weight to P establish a secondary dominatingharmonic. In order to as'sis't'this loose'elemen't in its dampeningoperationit is preferred to rotate the contacts in a direction ahead ofthe spring support 'so that inertia of both the loose element and the'centrifugally influenced contact tend to close the contacts'againwhenthe inot'or momentarily begirls to slow down after a separation ofthe con tac't's. Furthermore, in two of the embodiments illustrated itis preferred to provide a short spring of high frequency vibrationcharacteristics an not to vary the relative tension between the Switchcontacts throughout the range of speed adlostment, but rather to varythe amount of contrifugal force to which the movable contact issubjected so that'a make and break frequency for the contacts isprovided above 300 makes and breaks a second and which can "bemaintained atbeater'speeds as row as 100 to 150 R. P. M.

Referring more particularly to thedr'awings,

a road ir 'ixe'r such as that disclosed i the Bisley application Serial"No. 755,995, ew Patent No. 2615391, issued October 28, 1952, referenceto which is hereby made, is shown 'inoFigl 1 and comprl es general abase I l rotatably support iilg a bowl l2 thereon beneath a motor unitl3 which "drives two depending interdigitatin'g bearers "ll"di'sposed inthe bowl. The motor unit I3 is carried by a support I5 pivoted'a s at [8to fmovethfe heaters in and out of the bowl I2 and a handle fl"! issecured to the motor unit for removiiig and managing the motor unit andheaters rrom 'th'e haseandsupport. I I Between a rear cap member i8 andthe front pdftidfi of the motor unit [8 is located a rotatable speecontrol adjusting ring 20. As more particularly shown in Fig. '2, thisring is rotatably mounte upon the housing 'framesection 2| and isprovioed in; identical cam 22 on opposite sides thereof (Fig. 3) toreceive the ends 'o f a yoke 23 whose ester porti n 24 N is slida'blymouriteu na 'gliideopening 25 provided through a boss '26 in the'rearof'thecap l8. 7 At its'c'enter, an adjusting screw 21 is provided in theyoke Where "it is located in axial alignmentwith the armature shaft 2'8of lthe' m'o'tor. Rotationof the ring "20 varies the depth of the earns'22 with respects) the yoke 23 and moves the yoke 23 in fifid lllfli iilin axial direction in cooperation with a o'fifififfifisih SIif-ih Tl'lhead 'Of the ail 6 lusting screw 21 is the work 'point for adjusting thespeed control governors embodying the 'mventi'on.

Before describing the several embodiments of the governor itself,reference is made to Fig. 12 showing the wiring diagram in which theovernor comprises a pair of make and break contacts 3-! and 3 2, one ofwhich is electrically con-- nected to a collector or slip ringillustrated by :a circle 33, and the other is electrically to a secondslip ring illustrated by a circle 34. Connections from the motorcircuitto the slip rings are made by brushes 3'5 and 36 respectively,and these brushes are connected in parallel with a 260 ohm resistor 3'!and an arc suppressing condenser 3'8. The condenser absorbs the surgesof current which are caused by the mak mg and breaking of the contactand serves to reduce sparking at the contacts, whereas the l esistor 31serves as aballast resistor to carry part of the current and therebyreduce the voltage drop across the contacts.

I An on and off sivi'tchlfl is connected in series with the centrifugalcontacts but in parallel with the condenser 38 so that any tendency forthe switch 40 to are when opened under load will be cushioned by thecondenser. Otherwise, the network ofthe governor contacts, condenser,resistance, and 01'1" and *off" switch is -connectecl in series with thefield windings It and the armature windings 42 of the motor. It willthus be observed that the governor make and break contacts are adaptedto make and break the motor circuit and by "so doing they control thespeed of rotation of the motor by opening above a certain speed andclosing below that speed.

Various speed-settings throughout an armature speed range ofapproximately 2000 to 15O00 R. P. M. are accomplished in one embodimentby varyingthe position of the centrifugally influ- 'cnced elements inthe governor which as shown in Figs. 2 to 5 "comprises a body 43 madeofan insulating material such as Bakelite having a hub portion 44 securedto the armature shaft 28. 'I 'he slip rings mentioned in connection withFig. 2 'are indicated at 33 and '34 where they constitute inserts castintegrally with the Bakelite when the body is formed. A radiallyextendingflange 45 on the body carries a multiplicity of fan blades 46around its periphery designed to rotate in one direction to circulatecooling air with greatest eflicienc'y'and provides a cavity 41 in theend face thereof in which is mounted the governor contacts upon brackets'48 and 50. The slip ring 33 is provided with 'a radially extendingflange 5! which is connected by means of rivets 52 with the bracket 48to make electrical connection therewith, and the slip ring 3 is providedwith a radially inturned flange 53 which is electrically connected tothe bracket by a securing rivet 54 extending through the hub 44 of thegovernor body.

In the embodiment shown in Figs. 2 to 5 inelusive, both brackets carryleaf springs, an arc'uately and inwardly curvedfle'af spring 55 upon theouter bracket 48, and an outwardly tensioned leaf spring '56 carriedbythe bracket 50. The two springs carry "the governor contacts 5-! whichare preferably constructed of a suitable metal such as tungsten or an"alloy adapted to break the current repeatedly for long periods of timewithout pitting.

The spring members 55 and 56 are preferably iim'd of tempered steel andare supported eccentrically with respect to the center or axis ofrotation of the shaft 28 with the springs pointing in the direction ofrotation of the fan as indicated by the arrow 58. In their eccentricposition, centrifugal force tends to move both springs radiallyoutwardly since this force acts upon the mass of the springs andcontacts. Consequently, at high speeds, whenever the inner springiii isfree of restraint the springs will occupy the relative position shown inFig. 5, in which the outer spring has flexed outwardly under centrifugalforce and the inner spring 56 as urged both by its own tension and bycentrifugal force follows the outer spring outwardly, depending upon theposition imposed upon it by a pull rod 60 operated by a control lever B!pivoted to a bracket 62 and provided with an insulating button 63located approximately at the center of rotation where it rides againstthe head of the yoke carried screw 21. Thus a the yoke. 23 is movedaxially back and forth it displaces the control lever Gi in arelationship by which the pull rod 69 moves the contact upon the spring56'with respect to the contact upon the spring 55.

It will be noted, as shown in Figs. 4 and 5, that the outer spring 55 isdisposed in a position substantially chordal to the circle transcribedby the contact 51 carried thereby when rotating and, as alreadymentioned, this position is one in which the free end of the spring 55points in the direction of rotation. The contacts because of the naturalinwardly curved resting position of the spring 55 and the normaloutwardly curved position of the spring 55, although drawn inwardly bythe pull of the pull rod 6! are normally in contact with each other.When the "011 and off switch 49 is closed, current passes through thecontacts to energize the motor and rotate the armature. speeds up due tothe impressed current and, as the armature begins to rotate, the spring55 is subjected to centrifugal action. This spring tends to moveoutwardly more and more as the speed increases until a speed is reachedat which the contact upon the spring 56 is restrained against furthermovement outwardly by the setting of the control lever 61 inrelationship to the yoke 23, whereupon engagement between the twocontacts 51 is broken.

The major portion of the current theretofore passing through the motoris thereby stopped and the motor tends to slow down. With the slow-down,the tendency of the sprin to continue to run at the speed imposed uponit consti- I tutes an inertia efiect which tends to close the contact 5?prematurely with a pronounced wrapping action. This inertial influenceis in a direction for assisting the tension of the spring 55. Thisinertial action serves as an additional momentary force to increase thefrequency with which the spring 55 operates to make and break thecontacts 51.

The morerapidly the contacts make and break the smoother will be theoperation of the motor at any given speed. In those instances where ashere the spring 55 is given a curved contour, fiexure under theinfluence of centrifugal force tends to change or dampen the potentialharmonic of oscillation suficiently to minimize any grouping tendency ofthe makes and breaks in the system. However, it is preferred to punch anopening at in the upper spring at a distance spaced from the contactabout one-third to onehalf way toward the bracket 48, which aperture Thearmature quickly divides the potential vibration of the spring intodiscordant portions having different moduli of vibration. The opening,however, is not enough to weaken the spring materially but it is largeenough to introduce a secondary moment of flexure. Moreover, a smallbrass rivet element 65 is located in the opening with the head disposedradially inwardly and the loose end thereof flattened so that the rivetwill not fall out of the opening yet be loosely mounted therein tojiggle freely under the influence of the springs vibration in thespeed-ups and slow-ups of the armature shaft induced by making andbreaking the contacts.

It has been noted that with this rivet thus located, all tendency formakes and breaks to be grouped is eliminated throughout the speed rangeto which the governor contacts may be set to break. The looseness andseparate mobility of the rivet as imposed upon the spring in itsoperation under the influence or centrifugal force dampens any recurrentperiodicity inherent in the spring action without setting up anydominant modulus of its own.

As the result of these constructions and arrangements of elements,pulsation, spurting or loping in the motor is eliminated at beater shaftspeeds as low as 100 R. P. M., and no beat effect is engenderedthroughout the range of adjust ment when the motor is operated upon A.C. current.

In Figs. 6 and 7 an embodiment of the invention is illustrated in whichthe centrifugal element is balanced to be adjusted by rotation about anaxis located cit-center with respect to the normal axis of rotation ofthe armature whereby the centrifugal effect upon the centrifugalresponsive elements is Varied without varying the tension upon thespring or its natural high modums of vibration.

In this particular embodiment one of the contacts Sla is carried rigidlyby a bracket 50a mounted upon an insulating disc 65 rotatably mounted bya rivet 61 similar to the rivet 54 shown in Fig. 2. This rivet is inelectrical contact with a bracket 63 which supports the spring 55a.Rotation of the disc is accomplished by a push rod 623a operated by acontrol lever 61a urged outwardly by a torsion spring i8 intertwinedbetween the lever Bio and the pivotal support bracket 62. The normalresting position of the centrifugal control is indicated in Fig. '7 towhich position it moved by the action of the torsion spring it.

Whenever the yoke 23 is moved inwardly against the button '53 on thecontrol lever tla the disc 55 is drawn to the position shown in Fig, 6.The normal resting position is thehigh speed setting as shown in Fig. 7,whereas the position shown in Fig. 6 is the low speed setting.

The tension imposed upon the spring 55a to force engagement between thecontacts 57a is determined and maintained constant at a factor in whichthe spring will separate the contacts under centrifugal action as shownin Fig. 6 at a motor speed of approximately 2700 R. P. M. to operate theheaters at a little less than200 R. P. M., preferably between 15:) and200 R. P. M. Then when the disc 55 is rotated in clockwise directionabout its own axis El as when the yoke 23 is moved outwardly by the cam22 to attain a higher speed and the control lever Sta follows theinfluence of the trsion spring it, the direct radial component or angleof centrifugal effort upon the spring is reduced, thereby making itnecessary for a higher speed to be'attaine'd again beforesuflicientcentrifugal influence upon the spring is again attainedtocause separationof the contacts.

Thus, although the spring requires at all times a predetermined degreeof centrifugal influence for it to separate the contacts, the speedcontrol varies with the angularity of anincreasing or decreasingcentrifugal force upon tie spring. Spoken of another way, the spring isforeshortened at higher speeds to the direct radial centrifugal forcecomponents and a higher speed is required before the component orcentrifugal force effective upon the spring is great enough to causeseparation of the contacts.

In view of the fact that the tension upon the spring-35:1 never varies,this spring can be greatly shortened to increase its modulus ofvibration. In fact, it can be shortened enough that it makes and breaksthe contacts as much-as 600 times a second at the lower speeds and, inthe preferred embodiment as shown, a rivet 65' is also provided asalready described to assure elimination of any grouping tendency thatmight be present with the spring.

With the embodiment illustrated in Figs. 6 and 7; afurtherefieot worthyof note is present. The inertial action-of the spring closing thecontacts when the motor begins to speed up is dispensed with above thelower speeds. This transpires when the supporting point on the bracket68 and the contact carried by the spring 65 pass apoint of equidistancefrom the axis of armature rotation. The point on the bracket consideredin this connection is that point where the springbegins to flex.

Referringto'Figs. 8 to 11 inclusive, a centrifugal'responsive device isillustrated comprising a capsule 80 made preferably of metal having acontact ring 81 in the closed end thereof. A fused glass ring 82closingtheopen end of the capsule supports a tubular atmosphereevacuation element 83 and this tube in turn supports at its inner endthe stationary end of a fiat spring 551; whereby its free end carries acontact 51b in juxtaposition to the ring 8|.

The formation'of this device enters into the invention since the spring.551) is mounted upon the tube 33 by which the atmosphere inside of thecapsule 813 is exhausted or established. The spring 5522 has slightrecesses 84 on its edges into which the end of the tube 83 isswaged asatv 85. The recesses define shoulders 19 which limit the depth to whichthe spring is inserted into the tube, and the inserted'portion'of thespring is held snugly in the tube 83, the width of the spring beingslightly in excess of the inside diameter of the tube sulliciently sothat the spring is supported in a way equivalent to a press fit. Thisleaves openings on opposite sides of the spring through which gases orliquids can be moved in or out of the capsule.

As shown in Fig.8, the tube83 has been connected to an evacuating deviceand. preferably Freon has been injected into the capsule to provide anarc quenching inert atmosphere. Once the Freon or any other suitableinert atmosphere is in the tube and the tube is purged of all oxygen,the outer end of the tube 83 is squeezed shut as at 37 to seal theFreonin there in a well-known manner.

As shown in Figs. 9 and 10 there is an appreciable space between thecontac i?) and the contact ring 8!. The capsule after it is formed asshown in Fig. 1c is mounted in an anvil 9! iii carried by a masterrotating element such as that indicated at 99 in Fig. 11 in whichposition the capsule is connected in series in a circuit such as Fig. 12of a test motor by one connection being established to the tube 83through a spring clamp 92 engaging the flatt po tions 81 thereof, andthe other conneeti o r estab lished by contact between anvil the wall ofthe capsule. A lever pivoted -t as oilcenter of the axis of rotation ofthe rotating ele ment 98 as indicated at $5, carries at its outer end aswaging piston 96 which reciprocates in supported relationship through amounting ring 9?. lhe piston 96 is capable of moving cut wardly againstthe bottom side of the capsule to as at as to flatten same and swage thecontact ring 8! upwardly when inward pressure is directed against the S3of the lever for that purpose.

When the capsule is thus mounted upon the test or sample motor in thismanner the current is turned on and the motor begins to rotate slowlyunder the influen e of current passing through the ballast resistor 31'.Pressure is then applied against the lever Q as at and a piston 36forced upwardly to swage the ring contact 8! into engagement with thespring supported contact 51?). When this engagement is established, themotor begins to run upon current passing through the contacts. Thisspeeds up the motor and means or" a tachometer secured to the motorshaft or a heater shaft the speed setting of the capsule can bedetermined. Upward displacement of the staging piston 95 is continueduntil the minimum low speed desired is read upon the tachometer. By thisprocess of adjustment the correct tension is imposed upon the spring 55band thereafter will remain a constant. All that remains to be done tostop the motor, remove the capsule mount it in a motor as shown in Fig.8 where the capsule is mounted upon a disc for rotary displacement in amanner similar to that described in connection with the embodiment shownFigs. 6 and 7.

Not only does the provision of such a capsule as that shown in make itpossible to adjust all capsules to a predetermined speed upon a mastertest motor and thereby sl pw sequent adjustments in individual otors,but the arc suppressing qualities of the inert atmosphere surroundingthe contacts eliminates all possibility of arcing and increases ii thelife of the governor contacts. Fur the governor contacts are not containforeign particles and debris carried by ing air that is circulatedthrough t by the fans :26.

Although vacuum may be employed in the capsule so, such requires apurification of all elements which is not necessar when Freon is used,or an inert gas or atmosphere which will not react appreciably with thematerial of the contacts and capsule under electri arc discharge.Furthermore, where the arc suppressing atmosphere is provided, theballast resistace can be increased to as much as ohms withoutdeleterious effects upon the contacts bib d 8t. Increasing theresistance of the ballast re stance enables ballast resistance tooperate much cooler even at comparatively low As matter of fact, theballast resistor not en- 'rely necessary when the inert atmospherecapsule so is employed. It is preferred, however,

ated by the coolmotor x. we

to use a surge condenser 38 at all times, as shown,

of approximately .08 mid. capacity to provide sharp breaking of thecurrent.

Consequently, having thus described the invention and certainembodiments thereof, it will be readily apparent to those skilled in theart how the objects set forth are attained and how vari ous and furtherchanges and modifications may be made to accomplish the objects setforth with out departing from the spirit of the invention, the scope ofwhich is commensurate with the appended claims.

What is claimed is:

1. A speed control governor comprising a body rotatable about apredetermined axis, collector rings upon said body, a centrifugallyactuated switch mounted on said body at a point spaced from the axis ofrotation and including a leaf spring having an aperture thereinintermediate its ends, a pair of contact elements one of which issupported on the spring adjacent one end thereof, said contacts beingconnected electrically with said rings, and a freely movable elongatedelement extending through said aperture in substantially a radialdirection and upset upon the opposite ends to hold it loosely in placeupon said spring, said element having a weight component less than theweight of said spring.

2. A speed control governor comprising a body rotatable about apredetermined axis, collector rings upon said body, a centrifugallyactuated switch mounted on said body at a point spaced from the axis ofrotation and including electric make and break contacts and an elongatedspring carrying one of said contacts adjacent one end of the spring tocooperate with the other contact, and an element loosely mounted uponsaid spring at a point intermediate its ends for limited lateralmovement in a direction transverse to a radial line passing through it,said element having a weight component less than the weight of saidspring.

3. A speed control governor comprising a body rotatable in one directionabout a predetermined axis, collector rings upon said body, acentrifugally actuated switch mounted on said body at a point spacedfrom the axis of rotation and including an elongated spring having areduced cross sectional area intermediate its ends and a pair of contactelements, one of which is supported on the spring adjacent one endthereof, one of said contact elements being connected electrically withsaid ring, and a freely movable elongated element loosely mounted uponsaid spring at said reduced cross sectional area for limited movement ina direction longitudinally of said spring having a weight component lessthan the weight of said spring and operating to oppose harmonic cyclingof the spring without setting up one of its own.

4. In a centrifugal switch the combination of a rotary member, a pair ofcontacts movable with respect to each other, a resilient elementmounting one of said contacts upon said member for rotation therewith ata location disposed eccentric to the axis of rotation of said rotarymember, and means carried by said resilient element including a memberloosely secured to said element and carried thereby at a point ofresiliency on said element.

5. In a speed regulating apparatus for an appliance driving electricmotor, a pair of contacts in circuit with the winding of the motor androtatable with its armature, a leaf spring carrying one of said contactshaving its free end foremost in the'direction of rotation of the motorarmature and, its anchored end trailing thereto, said leaf springcarrying one of said contacts being at all times free to respondcentrifugally and inertia-11y to the rotation and variations inrotational speeds of the motor armature, and said leaf spring having anormal curvature and spring tension opposing the centrifugal effects ofsaid armature rotation, said normal curvature and spring tensionreceiving inertial assistance from the weight of the free end of thespring during deceleration of the armature to respond by a wrappingeffect of its foremost free end by accelerated movement of the contactcarried thereby radially inwardly momentarily ahead of the normalmovement of the contact under declining centrifugal force, and means forsupporting the other contact at a predetermined position against outwardcentrifugal movement thereof. 7

6. In a centrifugal switch the combination of a rotary member, a pair ofcontacts movable with respect to each other, a resilient elementmounting one of said contacts upon said member for rotation therewith ata location disposed eccentric to the axis of rotation of said rotarymember, means for shifting the contacts to change the location at whichthey engage with respect to the axis of rotation, and means carried bysaid resilient element including a member loosely secured to saidelement at a point of resiliency of said element.

7. A speed control governor comprising a body adapted to rotate in onedirection, collector rings upon said body, a centrifugally responsiveswitch mounted on said body including a pair of contacts connectedelectrically with said ringsand a resilient element disposedeccentrically to the axis of rotation of the body, said resilientelement being supported on the body at one end and supporting at itsother end one of the con-' tacts, said contact leading said supportedend of the resilient element during rotation in said one direction, andmovable solely in response to centrifugal and inertia forces duringrotation of said body, and means for supporting the other contact at apredetermined position against outward centrifugal movement thereof.

8. A speed governor for a motor comprising a rotatable element mountedfor rotation about a predetermined axis of rotation in association witha part of a switch adapted to be connected in circuit with said motor.

9. A speed governor for a motor comprising a rotatable element mountablefor rotation about a predetermined axis of rotation, a member mountedfor pivotal movement about a second axis located eccentrically to thefirst axis, a centrifugally influenced switch member carried by saidmember including a leaf spring, said spring being movable by said memberfrom an' approximately radially extending position to a positionapproximately normal to the radius with respect to the first axis ofrotation, said switch member being adapted to be connected in circuitwith said motor.

10. A speed governor for a motor comprising a rotatable elementmountable for rotation about a predetermined axis of rotation, a membermonted for pivotal movement about a second axis located eccentrically tothe first axis, a pair of switch contacts carried by-said memben one of;said contacts being supported; on a; centrifugally influenced resilientcontact support, said contacts being maintained under a, constantclosing pressurewhen resting and at their highest speed, adjustment,saio. switch member being adapted to be connected in circuit with saidmotor;

11.; A centrifugalswitch comprising a sealed capsule: having apredetermined atmosphere therein, a movable switch contact therein, saidcapsule having an electro-conductive section'collapsed over a portionthereof inwardly towards said contact.

12. .A: centrifugal switch comprising a sealed capsule having. apredetermined atmosphere therein, a resiliently mounted switch contacttherein, a switch contact mounted inside and upon the wall of thecapsule, said capsule having an electro-oonductive section collapsedover a portion thereof to support the second contact in normalengagement with the first contact.

13. A centrifugal switch comprising a rotatable shaft, a memberrotatably carried by said shaft, a sealed capsule substantiallyevacuated of free oxygen mounted on said member eccentrically to theshaft, said capsule having a normally closed switch therein includingtwo contacts and a resilient element resiliently supporting one of theswitch contacts, said capsule rigidly supporting the other contact andthe resilient element with respect to each other, and external means forelectrically connecting said switch in circuit with an electromotivedevice, said capsule being mounted with said other contact disposedcloser i to the axis of rotation of said shaft than the resilientlymounted contact.

14. In a centrifugal speed governor, the combination including arotatable member carrying a sealed capsule having an oxygen freeatmophere therein, said capsule also having two cooperating switchcontacts movable with respect to each other disposed therein, aresilient element supporting one of the contacts and having apredetermined weight component influenced by centrifugal action when thecapsule is rotated bodily about the axis of rotation of said member,said capsule rigidly supporting the contact and the resilient elementwith respect to each other, and means for connecting said contacts in anelectrical circuit.

15. In a centrifugal speed governor the combination including arotatable member, a centrifugal switch element carried by said member,

said element comprising a sealed capsule evacuated of free oxygen, twocooperating switch contacts movable with. respect to each other mountedin said capsule and including a spring element supporting one of thecontacts, said element and its contact having a predetermined vibrationmoment under the influence of centrifugal force when the member isrotated, the spring being disposed eccentrically to the axis ofrotation, and means for connecting said contacts in an electricalcircuit.

16. A centrifugal switch element comprising a sealed capsule having twocooperating switch contacts therein movable with respect to each otherone of which is supported by a leaf spring having a predetermined weightcomponent influenced by centrifugal action when the capsule is rotatedbodily about a predetermined axis, and means for engaging said contactsin electrical connection including an upset portion upon the-wallgofsaid. capsule supportingthe other;

contact.

17. An electrical switchcomprising a capsule collapsible atroneend, aclosure-for the capsule including acollapsible tube, a spring contact918-.

ment rigidly carried at one end by said tube and extending into saidcapsule to a point withinsaid collapsible end, said tube being closed atits outer endafter free oxygen has been evacuated from, said capsule anda stationary contact element,

carried by a wall of said capsule at the collapsible endandcooperatingwith the first mentioned contact element.

18. An electrical switch comprising a capsule, a contact ring in saidcapsule. at one end, a closure for the capsule including a collapsibletube,

a spring-contact element carried by said tube and extending intosaidcapsula-into juxtaposition with said contact ring, said tube beingclosed at its outer end and serving as an electrical connection.

19. An electrical switch comprising a metal capsule, a closure for thecapsule including a collapsible tube mounted to extend through anelectrically nonconductive material, a leaf spring carrying a contact,said spring being mounted in the inner end of said tube and extendinginto said capsule, and a cooperating contact in said capsule fixed withrespect to a wall thereof, said tube being open to the interior of saidcapsule along the sides of the spring.

20. An electrical switch comprising a capsule, means for sealing thecapsule including a ring of electrically nonconductive material, a tubereceived longitudinally through said ring, a spring carried by saidtube, a loosely mounted element upon the spring, said spring being ofless transverse dimension than the outside diameter of the tube, andcooperating contact elements carried by said spring and capsule saidspring and cooperating contact elements being disposed inside thecapsule.

21. In a centrifugal control for varying the speed of an electric motorthe combination of a spring mounted switch contact, means for rotatingsaid spring mounted contact about a predetermined axis to subject sameto the influence of centrifugal force, and rotatable means for mountingthe spring mounted contact having an axis located eccentric to saidrotating means whereby to modify the response of the contact spring tothe centrifugal force.

22. In a centrifugal control for varying the speed of an electric motorthe combination of a spring element, a switch contact carried on theelement, a rotating member carrying said spring element and contactabout a predetermined axis subjecting same to the influence ofcentrifugal force, and means for mounting the spring element and contactfor rotation about a second axis located eccentrically and parallel theaxis of said rotating member whereby to foreshorten the effective lengthof said element with respect to a radially directed centrifugal force,the weight distribution of the last mentioned means being such that itremains in dynamic balance so that its rotation does not disturb thedynamic balance of the rotating member.

23. In a centrifugal control for varying the sad or" an electric motorthe combination in-- cluding member adapt-ed to be rotatably driven bysaid motor, means carried by said member for supporting a resilientelement having a switch contact, the influence of centrifugal forcebeing such as to cause said resilient element and con- 15 ta'cttovibrate, a second cooperating switch contact carried by said means, andmeans for moving the first mentioned means about a second axis locatedeccentrically to the axis of rotation of said member to vary thecentrifugal force component efiective upon the resilient element and itscontact and thereby varying the speed of the motor, said cooperatingcontacts being connected in the circuit supplying power to said motor.

FRED A. MASHERIS.

KALMAN TANKO.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,313,856 Cavanagh Aug. 19, 1919 Number Number Name Date" Dornet al. Dec. 15, 1931 Matthews et a1 Aug. 11, 1936 Charter Nov. 9, 1937Begerow Mar. 22, 1938 Foss Dec. 6, 1938 Von Schlippe Mar. 26, 1940 BeharNov. 18, 1941 Clayton, Jr. Feb. 3, 1942 Peck et a1. May 5, 1942 SchwinnJan. 16, 1945 Ferrell Dec. 28, 1948 FOREIGN PATENTS Country Date GreatBritain Nov. 2, 1905

